The present invention relates to a high-pressure valve device particularly for pressurized fluids.
In the field of high-pressure high-precision valves for pressurized fluids there are currently various kinds of valves with special characteristics in terms of the type of fluid and the exceptionally fine adjustments required.
Said valves have some shortcomings which, in particularly extreme situations of use, i.e. with fluids having a very high feed pressure and in the presence of very high pressure differences between the input and the output of the valve with a large passage section, create some problems which severely limit their use.
Currently available valves in fact are inadequate from the point of view of adjustment sensitivity, since for example in some solutions the coupling between the actuation screw of the adjustment handwheel and the slider for the opening of the valve is often constituted by a simple split washer. This fact considerably compromises the ability to finely adjust the opening of the valve, especially in the presence of high pressure differences, since a play of a few hundredths of a millimeter can make adjustment insensitive and difficult.
Furthermore, the slider does not move only along the axis of the valve itself, but often, proximate to the closure point, the force applied to the handwheel rotates the slider itself against its seat in the valve body, causing, after a period of use which is normally not very long, leaks inside the valve itself.
Any laminar leakage inside the valve requires specific provisions for its drainage, since there is the risk of losing the hydraulic balance of the valve, if any, thus compromising its functionality.
Other solutions provide for the direct actuation of a slider or shutter having various shapes, provided by means of membrane pneumatic actuators or hydraulic or electric servo controls.
Actuation with pneumatic actuators entails the disadvantage of the considerable surface required by the actuator itself, with consequent considerable increase in the size of the valve. The intrinsic poor adjustment sensitivity can at the most be reduced by adding a positioner which is rigidly coupled to the slider.
Actuation by using hydraulic or electric power to control a slider or shutter using linear hydraulic actuators or electric servomotors coupled by means of gearboxes for the necessary speed reduction of the motor, has an adjustment sensitivity which is extremely difficult to improve, even when high pressure differences are not present.